Sound-retarding wall elements

ABSTRACT

A sound-retarding wall element having outer sheets and a honeycomb core which is compressed to an irregularly folded shape to improve the sound insulating qualities of the element. Honeycomb spacers formed of easily broken material are inserted between the sheets along opposite side edges of the element to prevent collapse of the cone when the elements are attacked for transport or storage. A process for producing such soundretarding wall elements.

United States Patent Streck 1 Aug. 29, 1972 [54] SOUND-RETARDING WALL3,141,809 7/1964 Dimaid ..l81/33 G ELEMENTS 3,231,439 1/ 1966 Voelker..181/33 GA [72] Inventor: Friedrich Streck, Homburg vdr der 3,459,2748/1969 MacPhail ..181/33G Hohc, G r y FOREIGN PATENTS OR APPLICATIONSI73 Assignee: Rigips-Stempel GmbH & Co. KG, ,254,208 1/1961 France..181/33 G Dutzenbach, Messenhausser Stras- 3 Se 1 PrimaryExaminer-Robert S. Ward, J r.

Att MD all,H h&S tt 22 Filed: Jan. 12,1971 omey 6 (mg ers co 21 Appl.No, 105,859 11 ABSTRACT A sound-retarding wall element having outersheets 52 U.S. Cl. ..1s1/33 G, 181/33 GA and a honeycomb core which iscompressed to an [51] Int. Cl. ..E04b l/86 regularly folded shape toimprove the sound insulating 58 Field of Search ..1s1/33 R, 33 G, 33 GAqualities Of the element Honeycomb spacers fmmed of easily brokenmaterial are inserted between the [56] References Cited sheets alongopposite side edges of the element to prevent collapse of the cone whenthe elements are at- UNITED STATES PATENTS tacked for transport orstorage. A process for produc- 2,728,479 12/1955 Wheeler ..181/33 0 Suchswndwardmg elements 3,529,693 9/1970 Woodward et a1 ..181/33 G 6 Claims,6 Drawing Figures 1,925,453 9/1933 Mazer ..-.181/33 G 1,932,359 10/1933Thomson ..l8l/33 G 2,187,335 l/1940 Wagner ..181/33 G SOUND-RET'ARDINGWALL ELEMENTS This invention relates to sound-retarding wall elementsand in particular, to a sound-retarding wall element with at least onesound-retarding (proofing) core between essentially parallel sheets.

In a handbook by C. M. Harris, entitled Noise Control", publishedby'McGraw-I-Iill Book Company, New York, 1957, pages20-4, FIG. 20.2,there are shown a number of examples of sound-retarding wall elements.However, these well known wall elements are all expensive to produceand,due to their construction, not

' ibility and thereby of the sound-retarding quality .of thesufficiently sound'retarding. Furthermore, it is difficult a to stacksuch sound-retarding wall elements horizontally one upon the other, aseach wall element exerts a not inconsiderable' pressure upon the wallelement immediately below, increasing with the height of the stack andcausing the wall elements to be compressed in such manner as toadversely affect their sound-retarding capacity.

An object of this inventionis, therefore, the creation ofsound-retarding wall elements, capable of being produced from relativelyinexpensive materials in a simple process and having goodsound-retarding quality and further, in spite of the thickness requiredfor sound-retarding the elements have resistance against torsion and maybe transported and-stacked without adversely affecting theirsound-retarding quality.

In connection with sound-retarding wall elements, as described in thepreamble, the problem is solved in the following manner: the core is tobe composed of hexagonal shapes (e.g. in the manner of honeycombs), theaxes of the honeycombs are to be vertical to the outside sheets; thehoneycomb core is to be irregularly folded by pressure exertedvertically upon the outer sheets and, finally, spacers are to beinserted between the outer sheets, possibly also of honeycomb shape, andare to be glued to the sheets, the spacers consisting of absorptivematerial, impregnated with synthetic resin, hardened and in a brittlestate.

The sheets with which the honeycomb core and spacers are connected, maybe made in the usual manner of wood, press board, cardboard, gyproc,plastics, metals, etc. Material to be used for honeycomb core and spaceris generally known and is widely used for door cores, heat insulations,etc.

This invention is based on the new and surprising discovery that soundinsulation by means of a honeycomb core may be vastly improved if bypressure exerted vertically tothe outer sheets, the walls forming thehoneycomb core are so compressed that they are irregularly folde'd 'ordeformed respectively. In this manner, a totally'unexpected degree ofsound retarding is effected, e.g. by approximately 40 to 50 decibels.This feature may perhaps be explained by the fact that the semi-elasticfolded (deformed) walls of the core convert sound energy particularlywell into kinetic energy or heat energy and thus avoid resonance.

It is essential that the walls of the cells-forming the core, in theoriginal, uncompressed state, are approximately vertical to the outersheets.

' In the case of the sound-retarding elements, to which this inventionrelates and which may be utilized for walls, c'eilings,etc., the problemof storage and transport to the building site is solved in a simplemanner by honeycomb spacers, glued to the sheets, so that compressionmay beavoided, leading to a reduction in flexdeformed honeycomb core.The spacers must be so arranged so to be easily and quickly removablebefore utilization of the wall elements at the building site and withoutdamage to the wall elements.

Hitherto, in order to keep fixed dimensions in bodies of flexible heightor thickness, small blocks or moldings, suitably dimensioned, and of asolid substance, such as wood, metal, ceramic, plastics, etc., wereutilized, preferably at the edges and between the respective sheets. Insuch instance, the spacer must be fastened, either by gluing, screwingor nailing so that removal of the spacer before utilization of thesoundretarding wall element is very difficult. Where spacers are gluedand removed after storage or transport, damage may be caused to the coreor outer sheets, in particularly if the former consist of pressboard,cardboard, gyproc or plastics, by the tearing of the sheet at the spotwhere the spacers are pulled away. The removal of screws or nails, onthe other hand, requires an unduly long period of time.

Pursuant to the present invention, these disadvantages are avoided bythe use of honeycomb shaped brittle spacers.

On the other hand, the spacers are resistant against pressure in thedirection of the cell walls, so that the sound-retarding wall elementsmay be stacked to vertually any height. Onthe other hand, the spacers,by reason of their honeycomb shape, may be easily removed by lateralpressure, exerted by an instrument shaped like a stick andcan bedestroyed so that their distance spacing effect is terminated.

The remnants of the brittle spacers glued to the sheets need not beremoved but, after elimination of the central portion of the spacers,may be left within the now flexible interior of the wall element, asthey are not visible from the outside. The honeycomb structure of thespacer is of importance insofar as sufficient space must be availablebetween the individual walls in order that laterally exerted pressure bya suitable tool may split and break it away. The hexagonal structure,such as honeycomb, may be fabricated for both core and spacers in a welltested manner.

If the sound-retarding wall element, object of this invention, is to befabricated directly where it is to be utilized, the honeycomb shaped,brittle spacers need naturally not be employed.

The walls of the sound-retarding core are only partly folded in aspecial manner provided for in this invention. By the degree of folding,a compromise may be reached between the required mechanical solidity andstiffness on the one hand, and the desired sound-retarding effect on theother. In this way, the non-folded part of the'honeycomb shaped wallsprovides solidity and stiffness, while the irregularly folded part ofthe honeycomb shaped core provides the sound-retarding effect.

In the production of the sound-retarding cone, the walls may bemostadvantageously and economically made from paper, pressboard orcardboard as such materials may be easily worked and are light inweight.

The walls of the honeycomb structure of the spacers may best be madefrom paper, pressboard, cardboard or thin wood, etc., as such materialsmay readily absorb synthetic resin, with which the spacers are to beimpregnated, hardened and rendered brittle. Weakly glued absorptivepaper proved to be excellent material for the spacers.

Moreover, the aforesaid materials for the spacers have little specificweight so that the total weight of sound-retarding wall elementshereunder in storage or transport is only inconsiderably increased.

For the impregnation of the walls of the spacers, cut to the requiredheight and width, synthetic resin soluble almost completely in water,may be advantageously utilized. In this connection phenol resin,carbamid resin or duroplast, readily available in water soluble form,are most suitable. The sound-retarding efiect of the wall element'shereunder may be further increased by partly or wholely filling thehoneycomb cell structures with sound insulating material.

The sound-retarding wall elements hereunder may be constructed in thefollowing manner: to begin with, the walls of the honeycomb structure ofthe sound-retarding core are so compressed that they are'wholely orpartly folded; subsequently the core is tied to the sheets and, for'thepurpose of transport or storage, brittle spacers are fitted along theedges of the sheets, whereby at least one end of the spacer is connectedto the respective sheet.

However, the sound-retarding wall elements hereunder may also beconstructed in the manner hereinafter: to begin with, the honeycombshaped walls of the sound-retarding core are attached to the sheetsnon-folded; subsequently, spacers are placed at the edges of the sheets,glued or attached in whatever manner to at least one sheet; finally, andin a vertical direction to the level of the sheets, the non-folded wallelement is compressed to the height of the spacers so as to partly orwholely fold the walls of the sound-retard ing core and pressure ismaintained until the loose ends of the spacers, suitably prepared, makecontact with and are tied to the adjoining sheet.

Irregular folding of the honeycomb structure walls is best obtained byexerting even pressure, by means of a press, upon the whole of thehoneycomb core or upon the outer sheets honeycomb structure with waterdissolved synthetic resin and, in the case of phenolic resin, (solublein water up to the ratio of l to 3 by Volume) heat treatment of about150 C, is applied for about 15-20 minutes in order to harden the plasticresin. Temperature and duration of heat treatment depend on the type ofsynthetic resin employed. By means of this treatment, the honeycombshaped walls become stiff and brittle and, in consequence, are capableof supporting considerable even pressure exerted upon their edges,vertically to the axes of the cells, without breaking. However, pressureexerted upon the walls of the honeycomb structure, i.e. with a toolshaped like a stick, will cause the spacers to burst individually andone after the other, due to their lack of elasticity. This quality ofthe spacers makes them highly suitable for the sound-retarding wallelements hereunder, i.e. high stability in case of vertical pressure andinferior stability and brittleness in case of lateral pressure.

A sample product pursuant to this invention is explained hereunder withthe aid of the attached drawing in which:

FIG. 1 is a perspective view of a portion of a soundretarding wallelement with brittle spacers inserted along edges of the element;

FIG. 2 is a plan of the wall element shown in FIG. 1, with a sheetremoved, and showing spacers inserted along edges of the element;

FIG. 3 is a section taken on the 3-3 of FIG. 2;

FIG. 4 is a section similar to FIG. 3 and showing the spacers brokenaway in the middle by a suitable tool;

FIG. 5 is a perspective view of a honeycomb spacer; and- FIG. 6 is aperspective view of the spacer shown in FIG. 5 with the middle brokenaway, as in FIG. 4.

The wall element indicated generally by the numeral 1 in the drawingcomprises two outer sheets 2, which may be of wood, pressboard,cardboard, gyproc, plastic, metal or the like. Between the outer sheets2 there is placed a honeycomb shaped core 4 as sound insulation,preferably partly folded or deformed. The walls 10 of the honeycombshaped core 4, which are es sentially vertical to the outer sheets 2,may consist of paper, cardboard, plastics, or other material and, attheir edges, said walls are glued or welded or otherwise tied or securedto said outer sheets. The walls 10 of the honeycomb shaped core 4 arepartly folded. The width of the core 4 and extent of folding(deformation) of the walls 10 depends, on the one hand, on the degree ofsound insulation to be achieved and, on the other, upon the resistanceto bending of the wall element to be obtained. The extent of folding ofthe walls 10 depends on the material utilized and pressure exerted. Incase of the wall element 1 partly shown in FIG. 1, a spacer6, consistingof honeycomb shaped walls of absorptive material, impregnated withartificial resin, hardened and rendered brittle, is inserted along edge5. The width of the honeycomb is ordinarily between 1 and 1.5 cm, inorder that the spacer 6 may be easily broken away immediately beforeutilizing wall element 1.

In order to avoid shifting of the spacer 6 during transport ofhorizontally stacked wall elements I, said spacer is glued, welded orotherwise tied at opposite ends to the sheets 2.

Insertion of the spacer 6 along at least two edges of the wall element 1prevents free elasticity (flexibility), shown in FIG. 1 by double arrow7, which later assures sound-retarding quality, so that during storageand transport of the wall element, the sound-retarding quality thereofis not impaired.

FIG. 2 shows a view from above of wall elements 1, as in FIG. 1, a sheet2 having been removed in order to indicate the honeycomb shape of thesound-retarding core 4, as well as that of the spacer 6 inserted alongthe edge 5 with a similar spacer 6 being installed edge 9. Optionalspaces 4a and 4b are allowed between spacers 6 and the sound-retardingcore 4. The dimensions of the honeycombs and width, length and height ofcore 4 and spacers 6 are not drawn to scale. The width of the honeycombsof spacers 6 may be larger or smaller than that of the honeycombs of thesound-retarding core 4.

FIG. 3 shows a section of wall element 1, along the line 3-3, as shownin FIG. 2. In this drawing not only the partly folded honeycomb core 4is shown but also the spacer 6 inserted along the edges 5 and 9 of thewall element 1 for'the purpose of storage or transport. In thisconnection, it is pointed out that the degree of irregular folding ofthe walls 10 effected by deformation, need not be smaller than thedistance between the honeycomb walls. The folds may also touch eachother laterally.

While the section in FIG. 3 shows the wall element 1 during storage ortransport, and includes spacers 6, FIG. 4 shows the wall elementimmediately before utilization and the spacers broken in the middle asindicated at l l, ensuring free flexibility and restoring thesound-retarding quality. On interior sides 13 and 15, only remnants 6aand 6b remain of the severed spacers 6, without, however, impeding theflexibility or any other quality of wall element 1. If spacer 6 is tiedto a sheet 2 at one end only of the spacer, remnants would be found onthat side only. In this state, the wall element may be used inconstruction as the remaining remnants 6a and 6b are not visible fromthe outside.

In FIG. 5 and 6, spacer 6 is shown on a larger scale for the sake ofclarity, before and after separation with a tool.

or sheet-like objects with a flexible height (thickness) whoseflexibility is to be prevented during storage or transport and restoredprior to relevant use of said objects. Employment of spacers 6 isclearly independent of the material of the flexible core 4 and outersheets 2. Preferably, the same material should be used for bothsound-retarding core 4 and spacers 6, so that said spacers may befabricated from waste material derived from the production of theflexible core.

The widths of the walls of the sound-retarding core 4 and spacers 6 isnot critical. The width of walls 10 should be calculated in relation tothe required degree of sound-retarding and the corresponding resistanceto bending of the wall element. The width of the spacer walls should becalculated in accordance with the load weighing upon them vertically andthe lateral pressure required to destroy them, due to their brittleness.

This invention is not limited to the examples shown herein, inparticular not to wall elements with only two outer sheets and one core,but may also be applied, for example, to wall elements with more thanone soundretarding core, separated by interior sheets. Also, other thanhoneycomb structured cells may be employed.

lclaim:

l. Sound-retarding wall elements comprising two substantially parallel,spaced sheets, a core interposed Spacers 6 may, of course, be utilizednot only in wall I element 1 as described but in all cases ofessentially flat between said sheets, said core comprising elastichoneycomb cellsfhaving an axis substantially perpendicular to each ofsaid sheets, said honeycomb cells being folded over a portion of theiraxial length, and substantially rigid, brittle spacers interposedbetween saidsheets and fixed to at least one of the sheets along atleast one edge of the sheets, said spacers being formed of honeycombcells of an absorptive material impregnated with a synthetic resin andhaving an axis substantially perpendicular to said sheets whereby thespacers provide structural strength to the elements and are adapted tobe fractured to provide wall elements having elasticity to retard sound.

2. Sound-retarding wall elements as defined in claim 1 wherein the wallsof the core are formed of paper.

3. Sound-retarding wall elements as defined in claim 1 wherein thesynthetic resin is a phenolic resin. 4. Process for the production ofsound-retarding wall elements comprising the steps of forming. a core ofhoneycomb cells, compressing the core to at least partiall fol the oncorn cells ren er e ce s e tic, rxrngt e core to two para spaced sheetswhereby the axis of the cells is substantially perpendicular to thesheets, inserting brittle spacers formed of honeycomb cells of anabsorptive material impregnated with a synthetic resin along at leastone edge of the sheets and fixing the spacers to at least one of thesheets.

5. Process for the production of sound-retarding wall elementscomprising the steps of forming a honeycomb core, fixing the honeycombcore between two substantially parallel spaced sheets whereby the axesof the cells are substantially perpendicular to the sheets, insertingspacers formed of rigid honeycombed cells having an adhesive on at leastone end thereof, apply pressure to compress the honeycomb core to theheight of the spacers whereby the honeycomb cells are at least partiallycompressed to form folds over their axial length and maintaining thepressure until a bond between the sheets and the spacers is established.

6. Process as defined in claim 5 wherein the pressure is exerted tocompress the honeycomb core in a direction parallel to the axis of thehoneycomb cells.

1. Sound-retarding wall elements comprising two substantially parallel,spaced sheets, a core interposed between said sheets, said corecomprising elastic honeycomb cells having an axis substantiallyperpendicular to each of said sheets, said honeycomb cells being foldedover a portion of their axial length, and substantially rigid, brittlespacers interposed between said sheets and fixed to at least one of thesheets along at least one edge of the sheets, said spacers being formedof honeycomb cells of an absorptive material impregnated with asynthetic resin and having an axis substantially perpendicular to saidsheets whereby the spacers provide structural strength to the elementsand are adapted to be fractured to provide wall elements havingelasticity to retard sound.
 2. Sound-retarding wall elements as definedin claim 1 wherein the walls of the core are formed of paper. 3.Sound-retarding wall elements as defined in claim 1 wherein thesynthetic resin is a phenolic resin.
 4. Process for the production ofsound-retarding wall elements comprising the steps of forming a core ofhoneycomb cells, compressing the core to at least partially fold thehoneycomb cells over their axial length to render the cells elastic,fixing the core to two parallel, spaced sheets whereby the axis of thecells is substantially perpendicular to the sheets, inserting brittlespacers formed of honeycomb cells of an absorptive material impregnatedwith a synthetic resin along at least one edge of the sheets and fixingthe spacers to at least one of the sheets.
 5. Process for the productionof sound-retarding wall elements comprising the steps of forming ahoneycomb core, fixing the honeycomb core between two substantiallyparallel spaced sheets whereby the axes of the cells are substantiallyperpendicular to the sheets, inserting spacers formed of rigidhoneycombed cells having an adhesive on at least one end thereof, applypressure to compress the honeycomb core to the height of the spacerswhereby the honeycomb cells are at least partially compressed to formfolds over their axial length and maintaining the pressure until a bondbetween the sheets and the spacers is established.
 6. Process as definedin claim 5 wherein the pressure is exerted to compress the honeycombcore in a direction parallel to the axis of the honeycomb cells.